[SPARK-3827] Very long RDD names are not rendered properly in web UI

With Spark SQL we generate very long RDD names. These names are not properly rendered in the web UI.

This PR fixes the rendering issue.

[SPARK-3827] #comment Linking PR with JIRA

Author: Hossein <hossein@databricks.com>

Closes #2687 from falaki/sparkTableUI and squashes the following commits:

fd06409 [Hossein] Limit width of cell when RDD name is too long
[SPARK-3808] PySpark fails to start in Windows

Modified syntax error of *.cmd script.

Author: Masayoshi TSUZUKI <tsudukim@oss.nttdata.co.jp>

Closes #2669 from tsudukim/feature/SPARK-3808 and squashes the following commits:

7f804e6 [Masayoshi TSUZUKI] [SPARK-3808] PySpark fails to start in Windows
[SPARK-3762] clear reference of SparkEnv after stop

SparkEnv is cached in ThreadLocal object, so after stop and create a new SparkContext, old SparkEnv is still used by some threads, it will trigger many problems, for example, pyspark will have problem after restart SparkContext, because py4j use thread pool for RPC.

This patch will clear all the references after stop a SparkEnv.

cc mateiz tdas pwendell

Author: Davies Liu <davies.liu@gmail.com>

Closes #2624 from davies/env and squashes the following commits:

a69f30c [Davies Liu] deprecate getThreadLocal
ba77ca4 [Davies Liu] remove getThreadLocal(), update docs
ee62bb7 [Davies Liu] cleanup ThreadLocal of SparnENV
4d0ea8b [Davies Liu] clear reference of SparkEnv after stop
[SPARK-3731] [PySpark] fix memory leak in PythonRDD

The parent.getOrCompute() of PythonRDD is executed in a separated thread, it should release the memory reserved for shuffle and unrolling finally.

Author: Davies Liu <davies.liu@gmail.com>

Closes #2668 from davies/leak and squashes the following commits:

ae98be2 [Davies Liu] fix memory leak in PythonRDD
[SPARK-3825] Log more detail when unrolling a block fails

Before:
```
14/10/06 16:45:42 WARN CacheManager: Not enough space to cache partition rdd_0_2
in memory! Free memory is 481861527 bytes.
```
After:
```
14/10/07 11:08:24 WARN MemoryStore: Not enough space to cache rdd_2_0 in memory!
(computed 68.8 MB so far)
14/10/07 11:08:24 INFO MemoryStore: Memory use = 1088.0 B (blocks) + 445.1 MB
(scratch space shared across 8 thread(s)) = 445.1 MB. Storage limit = 459.5 MB.
```

Author: Andrew Or <andrewor14@gmail.com>

Closes #2688 from andrewor14/cache-log-message and squashes the following commits:

28e33d6 [Andrew Or] Shy away from "unrolling"
5638c49 [Andrew Or] Grammar
39a0c28 [Andrew Or] Log more detail when unrolling a block fails
[SPARK-3777] Display "Executor ID" for Tasks in Stage page

Now the Stage page only displays "Executor"(host) for tasks. However, there may be more than one Executors running in the same host. Currently, when some task is hung, I only know the host of the faulty executor. Therefore I have to check all executors in the host.

Adding "Executor ID" in the Tasks table. would be helpful to locate the faulty executor. Here is the new page:

![add_executor_id_for_tasks](https://cloud.githubusercontent.com/assets/1000778/4505774/acb9648c-4afa-11e4-8826-8768a0a60cc9.png)

Author: zsxwing <zsxwing@gmail.com>

Closes #2642 from zsxwing/SPARK-3777 and squashes the following commits:

37945af [zsxwing] Put Executor ID and Host into one cell
4bbe2c7 [zsxwing] [SPARK-3777] Display "Executor ID" for Tasks in Stage page
Fixed style of dev/run-tests
Merge branch 'master' of git://git.apache.org/spark into SPARK-3758
Improved dev/lint-windows-cmd